The Cruelty of Fate
by writerdragonfly
Summary: Erica Reyes died in the decaying old bank that had been abandoned years before, and Cora Hale, survivor despite the odds, lived. But the nature of fate is not always sweet, and instead sometimes cruel. Stuck in a body that does not fit, Erica struggles to be the sister that Derek needs.
1. Chapter 1

It happens while they sleep, bodies huddled together in a mess of sprawling limbs and tangled clothing.

At night, Erica wraps tightly around Cora's middle, under her shirt and touching the bottom of her breasts with the bare skin of her arms. Boyd wraps around Erica from the side, making a haphazard pile of them. Hands and fingers and mouths linger against soft flesh as they come together and they do not speak of what it means.

It's an odd sort of arrangement, but they crave the warmth and necessity of contact, skin to skin, like they cannot remember craving anything else.

Erica is the last to fall asleep that night-was the last to fall asleep most every night-though in truth it could be day and they would have no idea. Time passes slowly, achingly so, in the tightly controlled confines of the vault.

But it happens while they sleep on the night of the new moon, though they don't know the phase of it as they cannot see or feel for the walls that suffocate their wolves into silence. It happens as they huddle together in broken comfort wishing to be rescued more than anything.

* * *

Boyd is the first to notice, though he's lucky enough not to have changed at all. He calls attention to the bratty whine that Erica lets out when she blinks blearily awake, and it occurs to him that Erica's whine (for it could be no one else's) is coming from the quiet, snarky brunette instead of the blonde to which it belongs.

The first few days stuck in each other's bodies feels like a test, like they're to be scored on their ability to act like nothing has changed and that they belong in the bodies they're breathing from.

They don't know if their captors are aware that Cora and Erica are in the wrong places, stuck in each other's mostly unfamiliar bodies. Erica would not be at all surprised if the demon wolf with his glassy red eyes had the very intention of thrusting them unaware into bodies that do not fit, and she suspects that Boyd and Cora would agree if she brought it up.

But they don't talk about the wolves that play games with their minds as they taunt and leer at them from where they cannot be touched. Cora and Erica do not talk about the itch between their shoulder blades that screams out in agony for a body that is no longer theirs.

* * *

And time, though slow, _does_ pass.

Cora opens up like a blossoming flower when they fall into their exhausted heap every night, and they share stories of their childhood-similar and separate, shared and apart-and of _pack_.

Erica treasures the stories about Cora and Derek most, because of what it means to her Alpha, what it will mean when they're found and can share Cora with him like a prize, like a gift for coming to their rescue.

But their rescue is not quick. The pull of the moon is held away until they're less than human and less than wolf.

Conversation fades into hollow looks and wordless glances, until they're too far feral to breathe even a faint smattering of dialogue. _Until touch is the only constant left._

* * *

Cora, who had learned for the first time the truth of what reckoning had taken away most of her family, reacts wildly one night-she raves and slashes and bites-and does not return to them.

Erica sits wrapped in Boyd's arms with silent tears streaking across the face that belonged to Cora that night.

It is the last night she cries.

* * *

It is the last night for many nights, that she knows anything of who she is.

* * *

When her head is clear enough for thought, the first thing she remembers is Derek's face before her, four letters tumbling from his lips in the shape of a name that doesn't belong to her but the body she's forced to inhabit, forced to use as her own.

She thinks about telling him that she's not Cora, that the pack of wolves who killed the real Cora cast them into each other's bodies and left them there to rot in the misery of not fitting in the skin they were in.

But she _doesn't_. She remembers the look on Derek's face when he realised he wasn't alone, that Cora survived these years too, and she cannot take that unexpected joy from him. Derek deserves to have his sister back, damn it, and Erica knows in an instant that she has no other real choice.

Erica is dead and Cora survives.


	2. Chapter 2

Derek just knows that something incredibly bad must have happened to Cora after the fire, after she escaped into the woods and eventually, somehow, ended up in South America. She doesn't talk about it, refuses to say more than a few cursory details outside the location of the pack she'd been staying with and her Alpha's name.

He doesn't understand, not entirely, but he doesn't push it. He had his entire family stripped away and he's been given this piece of it back. She may not completely act like the Cora he remembers, but he knows he's nothing like the Derek she does either.

Sometimes she doesn't remember his fondest memories of her, and sometimes she seems to stumble over describing the ones she does and it almost feels like a lie. Like she doesn't remember, or maybe, perhaps, that she doesn't look on memories of Derek fondly at all.

Derek wouldn't blame her. He's the reason that everyone else is dead.

* * *

The more he thinks about Cora, the more he thinks about Laura. About the six years he spent with her as his Alpha, his protector, his _everything_.

He hadn't dated in that interim. He'd tried to. He remembers blind dates and Laura's comforting pushes. But memories of Kate always surfaced. Of the message on his voicemail, taunting him.

"_Oh, kid. I hope you didn't think we were going to last. It was only a matter of time before you got **burned**_**.**"

He had slept with nameless women and faceless men and at the end, he could barely breathe without tasting smoke on his tongue and fire in his throat. Laura saved him with a wry little grin and a comment on his lack of decorum and that had been that.

Of course, two weeks later, Laura dies and every step forward is washed away.

He's lived his life in flames and floods, and it feels like someone has brought him a set of wings with Cora to protect him from it.

* * *

Of course, nothing good ever lasts.

* * *

"Derek, no. Derek don't do this. You can't do this."

In a moment of lucidity, Cora scrambles to stop Derek and _Derek doesn't understand._

"You can't do this, Derek. I can't let you do this, I don't deserve this."

"What are you talking about Cora, nothing you could have done would mean-"

"_I'm not Cora!"_

And everything _stops._

* * *

"_I'm so sorry, Derek. I didn't want to do that to you, but I couldn't let you lose her. I couldn't. I couldn't save her but I tried. I tried so hard Derek but I couldn't save her. I wish someone hadn't taken us and thrown us in each other's bodies in that vault. I wish I had died instead."_

* * *

Cora-no, Erica-starts to spill the entire story. How she met Cora, how they spent the time locked away together clinging to each other. How Erica and Boyd became Erica and Cora and Boyd.

How Erica and Cora woke up inside each other's skin one morning and how Cora had tried to break them out wearing Erica's face.

How his sister died in Erica's body, with "don't tell Derek" on her lips.

* * *

_They're in the vault for six days when things change. _

_The girl Alpha is giggling as she throws the large canvas bag into the vault before shutting it again._

_The bag is several shades of red, dripping with viscous blood that the canvas couldn't soak up. It moves suddenly, jerky angles poking up in the bag that could only be elbows and knees._

_Erica isn't sure who moves first, her or Boyd, but they reach the bag in seconds, ready to tear it open and rescue their packmate._

_The girl inside is a stranger._

* * *

_The girl manages to free herself the rest of the way. Most of the blood is from a large cut across her abdomen, gaping wide, though her body is littered with scrapes and scratches and cuts. Her skin is mottled purple and blue, huge bruises flaring across her skin like a promise._

_But she's alive._

* * *

_It takes two hours before they talk to each other. She's skittish, and expectedly so. But eventually she opens up, her voice a little raw from what Erica can only assume was screaming._

"_Are you part of their pack?" She finally asks warily._

_"No, they kidnapped us from our Alpha in Beacon Hills." Boyd answers, and Erica is surprised. The more she thinks about it though, the less she is. Boyd is a comforting presence, and this girl obviously needs one now._

_"Is your Alpha a Hale?!" She suddenly yells, her eyes wide._

_"Why do you want to know?" Erica asks cautiously. _

_"I need to know, please." The girl finally says, and Erica can see her eyes spiking with tears._

_Erica shares a look with Boyd, then puts a hand on the girl's._

_"Our Alpha is Derek Hale."_

_The girl cries. Loud, ugly sobs that lodge themselves in Erica's chest until she wants to cry too. She doesn't remember moving, but soon both her and Boyd are wrapped tightly around the bloody wolf girl._

_"What's your name?" Erica asks once the sobbing stops. The girl's lips lift in a faint hint of a smile._

_"Cora. Cora Hale."_

* * *

_In the time that passes, the three of them cling to each other like life rafts. And perhaps that's exactly what they are. Little points of buoyancy to keep each other from going under._

* * *

_Erica knows Boyd's body like she knows her own. She knows the places that make him shiver and shudder and gasp. And, in time, she knows Cora's too._

* * *

_"Don't tell Derek..."_

* * *

She passes out again, and Derek doesn't know what to do. She wants him to let her die because she's not Cora and doesn't think that her life is worth Derek's Alpha powers.

But Derek looks at her and remembers Erica that day in the hospital. Remembers the way she was before the bite. The way she took to it. The way she changed.

And the way she spoke in Cora's voice.

"_I'm so sorry, Derek. I just wanted to give you your sister back."_

And she had.

* * *

Derek gives up his alpha power and status for Erica Reyes as she lies dying in his sister's body.

When she wakes up, it's to her hand in Derek's, holding it tightly.

* * *

"I'm so sorry I couldn't be Cora instead," Erica cries, burying her face in Cora's long fingers and sobbing.

"It's okay, Erica. Come here." Derek says, when what he wants to do is throw up. He pulls her into his arms and holds her, as if she's actually Cora, his long lost sister. He kisses the top of her head, remembering Cora and Erica both.

"Everything is going to be okay," he whispers into her hair.

It's not a lie, not for her. He will make sure she will be okay, even if... even if for him, everything is ashes again.


End file.
